Assuming you like shooters its a must buy, also a quick look at the score charts makes me realise just how many people are still playing this game
Well the bundle pack isn't that much, i see it offering a lot of play time. I would download the demo you'lll pretty much see if the full game is worth it after playing that. Personally i had been meaning to buy this for ages but just never bothered. I can't imagine i'd regret this purchase cause i can always come back to it.
Game modes maybe more:
Arcade mode has 5 planets consisting of 5 levels each. There is an easy difficulty that loops on easy, but if you play on normal the game keeps looping getting harder and harder.
Survival mode you basically shoot on a planet with one life and there seems to be a bunch of indestructible blobs.
Time attack complete a level in fastest time.
Bomber where you basically have guns disabled and can only use bombs.
Endless where waves get harder and harder this mode actually seemed pretty cool, it also randomises though i dunno if theres a limit to the randomisations.
There's a few multiplayer options.