A short (30) difficulty recalculation with a 2-minute block target is fatally flawed. Terracoin is going to have to deal with this.
There's a reason why bitcoin is at a 2 week recalculation. It is the forked blockchain resilience protection. For terracoin, 2 minutes x 30 blocks is a really short window to create a viable forked blockchain.
Consider the v1/v2 bitcoin blockchain event a few weeks ago. It happened about 1/4 of the way into the 2 week recalculation cycle. Suppose a couple of fringe miners decided to reject v2 blocks and go it alone.. The v1-only block fork now has to mine something like 1500 blocks at 1% of the original hashing capacity to reach the difficulty adjustment. Instead of being 10 days away, it is now 1000+ days away (3+ years) at their hash rate. This is a long time to hold out in order to get the difficulty drop. So far in the future there's no chance that a fork like this could cause significant trouble to the main chain's network.
But imagine if it was 10 blocks to recalculate (calculated at 60 per retarget minutes like terracoin).. the v1 miners managed to find two v1 blocks in a row just moments after the threshold was reached. On average they'd need to find just a few more blocks until suddenly their difficulty rate goes down and then start injecting them into the main chain network. If they got lucky they might even be able to get a few blocks ahead of the main chain.
Imagine the 0.6 and 0.7.0/0.7.1 clients suddenly following the v1 block chain (which is now longer, and they don't care about v1 vs v2). and 0.7.2+ following the other chain.
Long difficulty adjustment is a feature. It is there to allow the network to make sure an attempted fork never gets off the ground with a pre-populated blockchain. Rapid difficulty response is asking for trouble. And it's not the oscillation in difficulty that's the problem, but loss of anti-fork protection.
you're comparing two distinct networks here (as in hashrate).
If you were able to mine blocks with 10x times more hashpower than the total btc network, the same problem would exist ; this is exactly what we see with the trc network (10x times "nominal" hashpower increase occurs multiple times a day).
If you had 10x the total btc hashrate in your hands, you could possibly forge the 2016 blocks in less than 2 days, then publish your longest chain.
Bitcoin did not ran into this because it was popular enough (by beeing widespread / early adopted) before huge farms / dedicated hardware came up