if you're getting the same criticisms on project to project I'd be more worried. If you think the criticism on every project is lame and unjustified, welcome to the working world
Typically I look at the more recent body of work than the overall body, especially when critique is warranted "gee Dansack, you've been falling off from your usual reports. Perhaps you should try not calling in sick every Friday" but when it's time for an overall assessment, the whole body is considered, so if you're an .865 hitter and the other temps are hitting .333, I wouldn't sweat it to much.
The fact you care about it speaks well, so I think you'll be fine. If they make lame excuses not to make you permanent, F them, and find someone who'll appreciate your ethic.
As you write this, one of my evaluators wants to "talk" tomorrow for only a couple of minutes. This hopefully won't be so damaging. I have no idea what this is actually about. My parents think it won't be negative (their reasoning is that the guy is reaching out to me and would meet on his time, and I have 3 1/2 other months of great things...my dad thinks the guy just wants to make sure I'm not too stressed and that things in my personal life are going well).
On the last negative report I posted in the OP (it was recent)...a lot of that was out of my control. I don't want to blame a co-worker, but the inability for him to do a simple task made me look bad. It's something everybody in his position knows how to do, but he couldn't do it and I got hammered for "taking too long." Hopefully my evaluator understands.
As for our overall assessments...not sure how it's done. For my first 3 1/2 months, nothing but plusses. The last two weeks, I've been hitting .500ish. This takes a bit away from the near 1.000 I was hitting before. They always say they want to see overall improvement, so...yeah. Usually, people struggle initially and then improve. I was lights out for 3 1/2 months and am now experiencing the bump in the road.
To put a FBB joke at the end...I don't think showing him Matt Kemp's 2009 season (no lower than .292 avg - and a few months well over .300 - from April-August, then hit .224 in September/October) is going to help in the sense that "these things happen."