1. The first page after logging in says "To get started, type something in the Edit Box above and hit ENTER when you are done. Everything you create here will be visible to you and I because we are the only members of this loop." The last point on the page says "If you have any questions or feedback, just add a note in the Edit Box above and I'll make sure I forward it to the right people!"
Which is it? Private testing ground or feedback form? This isn't a good start, confusing and contradicting your new users.
2. The default/showcase loops are annoying. I don't want my account to be cluttered with tutorial content. An intuitive interface and clean documentation should be enough.
Worse, you cannot delete these default loops. I spent 10 minutes simply trying to remove the tutorial content without receiving "not found" or "permission denied" errors. Turns out you can only remove the shortcuts from the menu, not the loops themselves. I imagine this is because you implemented these as a single loop shared across all accounts rather than importing a copy of these loops per new account. Bad implementation - why are you presenting me with the functionality to delete the loop only to prevent me from doing so?
I would not clutter every new account with tutorial content. A new account should be perfectly clean so I can start using it, rather than wasting time trying to determine what are core pages vs. tutorial content. Also cannot remove the annoying "Loopy" page.
3. The transitions and animations are not cool. They are very distracting and slow down the use of the application by several factors. You said this project started a long time ago, and the way the UI tries to be fancy in my face seems to confirm this. An animation on every single mouse click is not acceptable since 2010+.
4. The hassle of just trying to kill the tutorial content imported to my new account, coupled with the in-my-face transition animations wasted the full amount of time I invest in trying out a new web app. The initial process frustrated me and chased me away from checking out the real product.
Sorry, I spent 15 minutes reading the landing page and exploring the first steps after logging in and got nowhere. That is too much time spent trying to evaluate a product and not seeing any progress.