In "* Learn Katakana using Vocabulary", level 5, I noticed that the English definitions of the extended katakana (ティ, ディ, トゥ, ドゥ) are nonstandard and inconsistent with normal romanization ("tee", "dee", "too", "doo"). On examination, it's clear that "tee" and "dee" are meant to be read like "see"; and "too" and "doo" are meant to be read like "zoo". But anyone learning kana is going to initially read "dee" as if it were デー, not ディ, and "doo" as if it were ドー, not ドゥ. These definitions are inconsistent with the rest (and therefore counterintuitive), and do not reflect general romanization standards. The common, intuitive, consistent, and generally accepted romanizations of these are "ti", "di", "tu", and "du", respectively.
In "* JLPT N4 Vocabulary", level 7, the definition of すると is given as "then". More accurately, and to prevent ambiguity, it should probably be given as "thereupon", "hereupon", or something similar. The other words in that level might benefit from being redefined as well. In level 3, the adjectives いたい and いそがしい are defined with "to be [adjective]" instead of simply "[adjective]", which is inconsistent with the other definitions, and during later review gives the misleading impression that one is being prompted for a verb.