Beautiful game. The hand-drawn environments show a sense of care to 2D games that only a few devs have matched. It is very rare to feel like you have been drawn than just watching you character do things on the screen, but the Alientrap devs have gone above and beyond with this.
The short little tutorial at the beginning is straight forward and controls are easy to grasp. The game introduces new elements very straight forwardly, allowing you to figure out what they do on their own rather than telling you, which keeps the element of discovery fresh in every level. The use this same concept for the enemies.
The level design is great, providing secrets like in retro 2Ders to discover which will give you a buff or extra life. There is no map or compass adding to the genuine "Lost and stranded" theme to the game.
If this wasn't enough to grab it, go check out the demo on Steam!