Compass works - Attitude indicator works for roll and pitch - speed indicator works if GPS is enabled and accessible. Attitude indicator, in addition to responding changes in roll and pitch, also responds to acceleration/deacceleration - - - and lateral "G" forces - - -- which, makes for some cool looking responses when youre driving around town BUT which have nothing to do with changes in attitude. So, the AI "banks" and "pitches up" as your car turns or accelerates . . .. . Altimeter and VSI work - marginally - and with a lot of lag in response-time to an initial climb. So, for example, a climb over an overpass at 60 miles an hour, wont produce any indicated changes in altitude or rate of climb until youre already on the other side (and descending) ! Altimeter appears to be accurate once the instrument is allowed to settle down . . . Have not seen ANY indication in the so-called "acceleration" indicator - - - it has sat unchanging whether in my car going from 0 to 60, or, in a B737 takeoff ! Cant tell if the units of measurement are too great for the meter to indicate anything or if this feature just isnt working . . . . but, in either case, indicated values are non-existant or unreadable. At the end of the day, the above make this app a little fun and pretty much useless . ... well worth the current "free" price.