To give the game some enhancements I added the last days two new features:
YOGA - yoga is a small robot randomly appears on planets.
If the player "contact" him, he dissapears and let play you one (of many) minigames.
There you can win points, upgrades, energy/shield...
Currently there are three minigames (simple 'select a box', memory, alien sweeper, [more to come])
Each minigame takes just a few seconds.
The other enhancement is a mini-mission-system.
From time to time an order appears the player can accept.
Orders like 'find a special alien type', 'catch a satellite in space', 'support an other space hero in a space fight', 'solve the mystery of an ancient obelisc', [sort of].
If finished the minimission in time you get a lot of points.