- The story isn't that interesting. Unless you really care about it you can skip every "comic" sequence without missing anything important gameplay-wise.
- The game is probably most fun on Hard difficulty.
- Forget everything you learned from shooters in the last decade (except Serious Sam). This game is all about hitting the enemy with overwhelming firepower while dodging rockets and gunfire.
- Get the grenade launcher and the gravity round upgrade ASAP. After that go for whatever suits your style. Recommended upgrades to have towards the later game however, are: Rocket Launcher with laser targeting and/or railgun.
- The upgrade that gives you bullet time when low on health can be situationally useful and can be bought in good conscience.
- Don't upgrade the shotgun. It can be used to take out small enemies that are alone but otherwise it's pretty useless.
- The gravity round will save you so many times if you use it well. Lob a grav round followed by an ordinary grenade (later rockets as well) at large packs of small enemies to clear them out and avoid getting swarmed, particularly in tight spaces. The gravity field will suck in your grenades/rockets too, guaranteeing a hit. It also stops larger enemies in their tracks, giving you a moment to react.
- You can be fairly liberal with your use of ammo, you can't kill anyone if you're dead.
- If you see a lone NANO pickup at the end of a hallway or sitting all alone in a room it won't harm to plonk some mines down if you have them.
- Don't fight with your back in a corner.