You're the driver of a semi-automatic roof repairing cart and you're undoing the damage caused by the meteorites. The roof of each house can only take so much damage before the entire house is destroyed.
Controls:
LEFT, RIGHT: Drive left and right.
UP, DOWN: Extend or retract the arm of the vehicle, holding the the repair rig.
Z: Use the repair rig on the roof. Make sure you're properly aligned with it (or get a perk which will do that for you)
X: Install an auto-repair unit (ARU) if you have some.
Scoring:
+25 points to undo the damage caused by one meteorite strike.
Level up after every 200 points scored. A randomly chosen house will grow in size upon leveling up. A perk shop dialog window appears.
Perks:

Automatic alignment of the repair rig with the roof level.
Double speed of all movements.
Sturdier vehicle which doesn't require you to retract the arm when moving leftright.
Toroidal topology: drive through the edge of the screen on the other side.
Auto-repair units (ARUs) for mounting on the roofs.

Pro tips:

ARUs won't last forever.
Some perks without some other perks make things more difficult rather than easy.

Updates:

1.4 (2020)
-- Longer theme music

1.3 (2016)
-- ARU can't be installed unless there is none on the roof or there is one with less than three hits to live

1.2
-- theme music plays in-game
-- limiting simultaneous meteorites above each building to three
-- limiting the height of buildings to 20 floors

This was my first ever contribution to the collection of PICO-8 consoles :-)
Thanks for playing!