Review: Kingdom Rush

This review was conducted on a Samsung Galaxy SIII running Android 4.1.2.

 Kingdom Rush is a fantasy tower-defence game for Android. No, wait, come back. I know we've seen a lot of these, but really, it's rather good. It's not original in any way, but it's got great artwork, doesn't take itself too seriously, and, most importantly, it understands its platform (but more on that later).

By now explaining the mechanics of a tower defence game is perhaps a bit unnecessary - we all know the rules, as Paxman might say - but it's probably worth pinning down the game's idiosyncrasies. KR eschews ideas of mazing (that is, placing towers freely in such a way that the enemies must take a longer path to navigate around them) and instead opts for pre-set paths and tower positions. There are four such towers: archers, who fire rapidly but do small amounts of physical damage; mages, who fire slowly but do large amounts of magical damage; artillery, which does large amounts of area-of-effect physical damage; and barracks, which produce hapless troops sent out to engage and slow the invaders. Each of these towers can be built and upgraded a number of times with gold picked from the pockets of fallen foes (automatically, mind - no Plants vs Zombies coin-clicking). At the highest upgrade level, you can choose one of two final destinations into which your tower can morph - for example, the barracks can become either a temple producing durable paladins, or a hut producing high-damage barbarians. Each of these final-level upgrades have themselves a number of abilities that must be unlocked for each tower - instantly disintegrating an enemy, for instance, or a large-area carpet bomb. While these additions (eight towers and around sixteen abilities) are hardly overwhelming in their complexity, they're enough to keep the levels lively and avoid  the needless over-complication often seen in games with a more dizzying variety of towers.

The opening phases of an early level. Note the two enemy spawn points and pre-set tower locations.

To keep things moderately fresh, you also have access to two other abilities which are independent of the towers. The first of these summons two conscripted reinforcements who act like the troops produced by the barracks - engaging two enemy creeps in hand-to-hand combat and thus slowing their progress along the route. The cooldown on this ability is short (about 10 seconds), meaning that it has a variety of uses such as reinforcing an overwhelmed barracks (enemies who don't have anyone to fight just run straight on), splitting up or stalling a group early on in their run, or in an emergency acting as a reserve guard against the Mob Who Got Away. The other ability calls down a rain of fire on the targeted location - effectively a panic button with a cooldown long enough to prevent it from becoming part of a strategy.

Finally, you have control of a hero unit, though 'control' perhaps implies more than there is. Basically, you can order them to move to a particular point, where they act just like the reinforcements or barrack troops. They have special abilities such as area damage or healing but use these automatically, meaning that outside of a quick retreat to cut off an escaping enemy they're pretty much set-and-forget. I get the feeling that perhaps there was meant to be a bit more to the heroes - they have an experience and levelling system, and there's a large number of them, each with different artwork and stats and abilities - but that the extra functionality was removed for some reason.

If that's true, then it's a shame for Ironhide (the developers), because it's one of the two things they chose to monetise in addition to the base price of the game (£1.30), and there's absolutely no reason to ever buy them (well, even less reason than usual for in-app purchases, I mean). They're certainly not necessary for completion, though they might make it easier.

£3.20 for what is effectively a skin is really quite cheeky in a paid-for game.

The other area they've tried to get you to pay for is in gems. These are dropped by creatures in the game when they die, and can be used to buy powerful one-off items, such as an ice wand that freezes all enemies on screen, or dynamite to throw at individual enemies. Again, it's quite unnecessary to ever buy them, as not only are the items themselves mostly pointless (I've had to use maybe three in total on the harder challenge modes) but you get such an abundance of gems from playing through the campaign levels that you could buy ten or twenty of every item and still not even notice that you'd spent anything. I suspect that this is deliberate, and I applaud the decision - as it stands, choosing to use the gem or hero store has only a cosmetic impact on gameplay, and is effectively a nice way of tipping the developers extra for making a game you enjoy. If you don't want to pay more for a game you already own, it's kept out of the way where it will never disturb you.

But back to the game. There's a campaign mode, with a story which consists of a single sentence on the loading screen of each mission and is so dull and tired that I've already given it too much mention. Going along the campaign unlocks the various towers and heroes that you don't have to pay for, as well as a number of more challenging side-missions. Completion of each level awards one, two or three stars, depending on performance, and these stars not only act as a 100%-completion-drive-in-lieu-of-real-replayability (thanks, Angry Birds), but can also be used to buy various upgrades for the towers and abilities you already have. These range from the basic such as reduced in-game upgrade costs and increased damage to new passive effects, such as magic attacks also slowing the target or reinforcements gaining a ranged attack. You can reset these for no cost and reassign them at will, which is something I often found myself doing to get through a tough level. Each level also has two additional modes you can attempt having completed it in the story: a tougher version of the story mode, and an 'elite' version in which certain towers or abilities are denied to you. Completing each of these gives you an extra star, meaning that in theory if one hit a tough level one could go back and upgrade sufficiently to beat it.

The upgrade shop, with everything unlocked

The levels themselves are wonderful. I'm personally a sucker for the nice bright colours and cartoon-y style (recovering WoW addict, remember), and there's a wide range of locales and a wider range of enemies who all have different abilities, strengths and weaknesses. Occasionally you'll come across a Big Bad Boss who disables your towers unless you engage in a silly little quick-time event, but most of the time you'll be free to plan your next move without such distractions.

That's not to say that you'll be completely passive - you'll want to use that 10-second reinforcement ability as much as you can, and the enemies come at such a pace that you're never far off upgrading or building something new. The level of engagement is more-or-less perfect for a mobile device: sufficient - more than sufficient - to pass the time on a bus or train or tube, but not so demanding that you can't look up and check the next stop. This is what I meant by Ironhide 'understanding the platform'. They know when and why people are playing games on their phones and have built something to fill that gap.

They also show an admirable understanding of what the human finger can easily do. The menu system for each tower is simple, intuitive and clever. You tap once to open a little ring-menu around the tower in question, tap on the option you want and then again to confirm, thus preventing a jolt or just fumbling fingers causing precision problems on smaller screens. Compared to the interfaces in many touch-screen games it's superb.

However, it's not all good news. While for the most part the simple mechanics aren't so simple as to be boring, the game isn't terribly well balanced. With the exception of a couple of challenge modes where all other options were removed, I never once found myself needing to use archers - almost all levels could be beaten by alternating a large number of artillery and mage towers, and some even just by stacking mage towers. In theory this shouldn't be possible because the various resistances to physical or magic damage of the different enemies means that you should need a variety of towers, as should the existence of flying enemies, but artillery is simply so much better than archers (though admittedly more expensive) that there's never any need to replace it. Oh, it can't hit the occasional flying opponent, but if you've dropped a few mages in that won't be an issue in any case.

Furthermore, I found myself suffering a fair few technical issues. No matter how many times I disabled the in-game sound and music (I have yet to find a mobile game with good enough music to merit the hassle of finding, untangling and wearing headphones), it was always enabled again whenever I started the game, occasionally drawing a few disapproving looks when I opened it on public transport and inflicted a few seconds of rubbishy 'epic' music on my fellow travellers. And I had to open it far more than I would like given its penchant for occasionally force-closing between levels (never during one, thankfully). In fact it's a bit of a resource-hog all round: if I didn't force-close every other running app, and clear them from the RAM, it tended to drop frames at an alarming rate. It's not as though I have an awful phone, either - I haven't tested this on older or mid-range devices but it might be worth keeping an eye on that refund timer if you can. Finally, if for some reason I did have to alt-tab out mid level (you know what I mean!) it would often restart the whole app when I switched back to it, destroying my progress. This is Not Good when the longer levels are around ten minutes long.

In fairness, the screen does get quite busy towards the end of levels, but it really should have been fixed.

None of that seriously damaged my having fun with the game, though - it was a minor annoyance at worst. The mechanics are simple enough that even a complete newcomer to the tower defence genre could pick it up instantly, but have sufficient depth to engage for a surprisingly long time. The artwork is also excellent for a mobile game, and due to its lo-fi nature will look great on devices regardless of resolution. For me this went beyond 'game I play on the bus' and became 'game I'll play when I have other, better things to do'. That's probably not necessarily true of everyone though - I enjoy tower defence more than most, I think.

Kingdom Rush is developed by Ironhide Game Studio and is available on Google Play for £1.30.