I’m going to start this review with a few friendly words of warning: unless you’ve set aside the rest of the day to play iOS games, whatever you do, don’t download Shellrazer (out now, $0.99). Seriously, Slick Entertainment’s latest — a frenetically paced side-scrolling shoot-’em-up starring a ginormous “War Turtle” covered with guns — makes for such a colossally compelling experience, you can literally sink hours into the game unbeknownst to yourself.

For anyone who needs an excuse to hop atop a ridiculously tooled-up reptile and start wreaking havoc (as if!), Shellrazer gets underway with a beautiful comic book style cut-scene that sets its story in motion. Rather surprisingly, Shellrazer’s is a love story — albeit one that’s hilariously off-the-wall. The game centers around a lovelorn Klang Clan “Shellrazer” (think a Sherman tank on legs) who longs to hook up with a purdy lady turtle. The problem is the female of the species are only to be found on the opposite end of a war-torn continent.

Proving that nothing stands in the way of a forty-foot tall, heavily weaponized War Turtle and true love — not even hordes of vicious goblin warriors — our hulking hero and his wrangler set off on a danger-fraught trek across the tumultuous kingdom. This epic quest spans 50+ levels that take in varied and visually diverse settings like deserts, mountains, jungles and more, all while serving up a heady blend of side-scrolling shoot-’em-up action, tower defense-style strategy and RPG-esque elements.

The initial handful of levels unfold at a fairly relaxed pace, which should give you more than enough breathing space to get to grips with Shellrazor’s shooting mechanics and control scheme(s). As the titular battle-hardened beastie trundles along automatically, players take control of a titchy Klang Clan warrior who perches atop his shell and mans a machine gun turret.

You have the option of either playing one-handed and dragging the gun around to fire a continuous stream of bullets at your foes, or to use use two hands, holding down on your weapon with one finger and tapping on enemies to target them with another. The first method is pretty easy to use — if a little inexact — while the latter allows for a lot more accuracy but feels somewhat fiddly until you get the hang of it. Don’t get me wrong though: with practice, both control methods work perfectly well. You can also rapidly tap on your War Turtle at any time to spur him onwards more quickly.

Basically, the goal of each level is to get from point A to point B without your War Turtle taking too much damage and being toppled by the goblins who attack from all angles. The action has a wonderfully frenzied quality to it, and it’s all but impossible to keep a goofy smile from your face as the screen fills up with droves of goblin soldiers, marching toward you on-foot, riding into battle in balloons and other wacky flying-machines, and taking potshots at you from inside makeshift wooden forts. Aside from annihilating everything that moves, there are also treasure chests to plunder and golden coins and crazy power-ups to collect.

As you stomp and blast your way through the Goblin Kingdoms, you’ll often have the option to briefly detour away from the main quest in order to rescue Klang Clan hostages. Liberate these warriors from the goblins’ clutches, and they’re only too happy to join you on your travels and pledge their weapons and unique skills to your cause. Although you free a dozen different champions — a powerful wizard, a shotgun-wielding hero and a mechanic who can carry out repairs on-the-fly, to name but a few — the teetering wooden platform on War Turtle’s back can only carry three passengers at a time, so you’ll have to think very carefully about which characters you should bring with you into the fray.

Between levels you have the opportunity to experiment with different combinations of companions, figuring out which one’s skills will be of the most use and work best together against the goblin hordes. Using the cash you earn during battles, you can also purchase weapon upgrades and power-ups and perks for your turtle. Tinkering around with your equipment and leveling up characters truly does add an immense amount of depth and an enjoyable learning curve to the proceedings.

Living up to their name, Slick Entertainment have turned in an über-polished and stupendously entertaining game; from the enthralling genre-bending gameplay to the sumptuous, playful visuals, the whole thing just screams quality and class. Furthermore, unlike a depressing number of iOS titles these days, the 1.0 release of Shellrazor actually feels like a “finished” product and boasts an impressively lengthy campaign from the word go, not to mention Game Center integration and a refreshingly unobtrusive IAP system. This is an iOS classic in waiting.

iFanzine Verdict: Shellrazer is a beautifully crafted and colossally compelling genre mash-up. If you like fun, you’ll love this game!