Timer, Speedometer and Powerup Store
These shots show a few interesting features that were removed, either to clean up the HUD, or because they were used exclusively for debugging purposes. Firstly, the speedo - this was used in debug mode, while tweaking vehicle prpoerties, in particular top acceleration and top speed.
Secondly, the timer, possibly used to impose time limits on completing missions, or more likely how quickly you destroyed everyone else. The timer is really still there, since you always get a 'time taken' value at the end of every round, which contributes to your ranking.
Finally, the 6 circles in the lower left of the screen were used to hold powerups, which could then presumably be activated when needed. They were removed in order to retain a cleaner looking HUD. Acknowledgements - Peter Morawiec.