Space Pioneer is a fun little run'n'gun top-down shooter (kinda like a twin-stick shooter, but with auto-aim instead of aiming with the second stick) with nice cell-shaded graphics, fluid controls and quite fun weapons. Only played a bit so far, but the action is fast paced, they chuck you into the action nice and early, and the frame rate and special weapon controls are all of good enough quality that you will be dancing around aliens and shooting/grenading the bejesus out of them from the word go.
There's an upgrade system, with more and more choices of special cooldowns (though the grenade/turret/medikit starting setup isn't bad, although I do want to sub out the turret soon) so you can beef up your spaceman. So far I've unlocked the assault rifle (standard weapon), the shotgun and the Tesla gun, and they all do things just differently enough that they feel OK. Though admittedly the Tesla gun feels like a straight upgrade of both (and the grenade launcher coming next might be better than all three, we'll see). Weapons use the overheat system, but they cool down pretty damn quickly, so you'll mostly be gunning, not just running while playing.
There's a base building system, but it seems pretty basic. Timers are in full force unfortunately.
There's no energy system though, so feel free to play as long as you want. I've gotten past the third boss in one sitting, and done the first "event" mission (which was actually pretty hard), and that took about an hour all up, so there's a fair bit of progression available from the get-go. Yay to no energy/stamina system!
Anyway, it's fast, it's fun, and they chuck you into the action quickly enough that it hasn't felt like a chore to find a challenge yet. There's a bit of a variety in enemies and mission objectives, though nothing amazing so far. Go somewhere, sometimes that somewhere is moving, and destroy everything while staying near that somewhere. Enemies tend to be slow melee, fast melee, and static shooters. Still, very well worth a look for a bit of furious blasting action. The bosses are quite nice, and the upgrades haven't felt like a cash grab waiting to happen. I'm quite impressed.
It's not exactly a complex game, there's only a few enemy types, weapon styles and planet types. But sometimes all you want is to run around shooting things until coins pop out of them, and that's exactly what this gives you, with a minimum of fuss or bother to get it.
((don't worry about the seemingly high gold cost for weapons/gear/character upgrades. From mission 11 onwards you will get more gold in one mission than you've seen all game. I actually grinded for about 20-30 mins and got 3.5k, which I then ad-doubled to 7k. Which was 10x more gold than I'd collected up until that point. Then I bought heaps of upgrades, went up in character level tonnes, now I've got the hand cannon/grenade launcher (nice), the flame thrower (which is a long-range weapon for some reason) and the laser cannon (not as good as you'd think). And plenty of character gear. So yeah, gold is pretty plentiful after a certain point, so this game is free-to-play approved by me))