Minigames certainly need more achievements (would be better if they counted towards a separate Minigame cape - basic, and master versions).
For The Great Orb Project, I'd suggest the following score targets:
(The targets are for scores in each altar, in the order in which they are played - Air, Mind, Water, Earth, Fire, Body, Chaos, Nature.
If you can't differentiate between solo/duo/>2 players, then simply go for the >2 set; if you can only do one tier, then the highest would best represent skill acquisition.
These scores are intended for 3-orbs per team, which isn't always the case, when playing with larger numbers of people, especially on the Mind altar)
Solo
:
Tier 1). 30 12 22 12 30 25 | 10 30
Tier 2). 40 16 30 15 40 35 | 24 40
Tier 3). 45 19 36 18 45 40 | 30 45
Tier 4). 50 22 40 21 50 45 | 35 50
Tier 5) [current World records - takes luck, as well as extreme skill, these may be a bit high, given even the best got them as flukes]. 58 26 44 23 53 52
Duo
:
Tier 1). 50 18 35 18 45 43 | 18 50
Tier 2). 55 20 40 20 50 48 | 22 55
Tier 3). 60 25 48 25 58 53 | 28 60
Tier 4). 66 30 54 28 62 57 | 32 66
Tier 5). 74 32 60 30 68 62 | 40 74
Tier 6 [current World records - given more for reference, than goals, as they require perfection in practice of extremely difficult mechanics, as well as massive luck). 78 36 64 34 75 72 | 45 78
>2
:
Simply taking the Duo targets, and starting with Tier 2, may work best, for this. Most of the significantly higher scores with more people, are due to more than 3 orbs spawning.
Ideally, it would include targets for other playstyles (at least walk, Legacy-Gop, and Ploord), as there are so many different game-modes, with their own highscores kept by the communities, but that's almost certainly asking for too much.
Going with the suggested targets would give people something to really aim for, and a reason to explore the game in depth, and will likely encounter those playstyles